The Soviet Union has announced the catastrophic failure of its latest space mission, with the crash of Soyuz 1 and the death of the cosmonaut on board.

Colonel Vladimir Komarov, 40, is the first known victim of a space flight. He was an experienced cosmonaut, on his second flight, and had completed all his experiments successfully before returning to Earth.

But within seconds of landing, just after he re-entered the Earth's atmosphere, the strings of the parachute intended to slow his descent apparently became tangled.

The spaceship hurtled to the ground from four miles up. It is likely that Colonel Komarov was killed instantly on impact.

Gold Star for heroism

A message of condolence from the Communist Party in Moscow described him as "a loyal son of our motherland and a courageous explorer of space."

He has been decorated posthumously with a second Gold Star for heroism, and his ashes will be buried at the Kremlin wall - one of the highest honours accorded to a Soviet citizen.

News of the death of Colonel Komarov was greeted with regret and concern in the United States. The head of the US space programme, James Webb, called for greater cooperation in space exploration.

The team of 47 American astronauts working at Houston in Texas sent a telegram of condolence to their Russian rivals.

Mystery crash

The announcement from Moscow gave few details surrounding events leading up to the disaster, and there remain a number of mysteries surrounding the last moments of the doomed flight.

The Soyuz 1 is known to be a new and heavier type of spacecraft, built as part of the Soviet attempt to land a man on the Moon, and Colonel Komarov was thought to be testing it when the disaster happened.

Correspondents in Moscow had indications that all was not well with the flight from as early as yesterday, when earlier reports on Moscow Radio suddenly stopped and there was no mention of the space flight for nearly 13 hours.

Experts have questioned why Colonel Komarov did not use an ejection system to get out of the spacecraft. The cosmonaut was also known to have suffered from heart problems.

It is now thought that the Soyuz 1 space flight had been dogged by problems from the beginning, and that the craft was not ready for manned flight.

But objections from the engineers were overruled by political pressures for a series of space feats to mark the anniversary of Lenin's birthday.

The Soviet Union continued to dominate the space race for another two years, until the United States put the first man on the Moon with the Apollo 11 mission in 1969.

Since the break-up of the Soviet Union, Russia and the United States have increasingly pooled resources and technology in space.

The two nations now share a joint permanent home in space, the International Space Station, launched in 2000. It replaced the last symbol of the Soviet space programme, the space station Mir, which was allowed to fall back to Earth in 2001.